It's just like that in real life. Whenever you buy a car, new or used, you always get a bucket of paint with it, and of course any body shop expects you to bring your own paint, how else would one go about getting it?
There was a pink cheap hatchback in the used car lot earlier today for me. I don't think it was a Fit or anything, but I was tempted to buy it simply to get the paint chip.